Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide |
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| Authors: | Takuma Tahara Dr Shuichi Suzuki Prof?Dr Masatoshi Kozaki Prof?Dr Daisuke Shiomi Dr Kenji Sugisaki Prof?Dr Kazunobu Sato Prof?Dr Takeji Takui Yota Miyake Prof?Dr Yuko Hosokoshi Prof?Dr Hiroyuki Nojiri Prof?Dr Keiji Okada |
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| Institution: | 1. Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Osaka, 558-8585 Japan;2. Department of Physical Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka, 599-8531 Japan;3. Institute for Materials Research, Tohoku University, Aoba-ku, Sendai Miyagi, 980-8577 Japan |
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| Abstract: | The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, ( DAA-PTZ ) + -NN? MBr4? (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh3 followed by oxidation with the thianthrenium radical cation ( TA+? MBr4?). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=?2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=?7 K and J5/kB=?4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet ( DAA-PTZ ) + -NN . |
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| Keywords: | electronic structure magnetic properties radical ions redox chemistry structure elucidation |
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